Panel coating

ABSTRACT

A method for coating of a floor panel and a floor panel produced by the method. A method for producing a laminated product, for example a building panel, preferably a floor panel. The method includes applying a paper on one side of a wood fiber based core, e.g., an HDF panel, creating a décor on the paper by a digital printing process, applying a resin, preferably a melamine formaldehyde resin, on the paper, heating the décor and the paper with the resin, preferably by using an IR lamp; and applying heat and pressure in order to cure the resin and thereby obtain a laminated product. Also, alternative methods for producing a laminated product, and such a laminated product.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application is a continuation of U.S. application Ser. No.14/237,617, filed on Feb. 7, 2014, which is U.S. national stage ofInternational Application No. PCT/SE2012/050896, filed on Aug. 23, 2012,which claims the benefit of Swedish Application No. 1250007-0, filed onJan. 9, 2012, and the benefit of Swedish Application No. 1150774-6,filed on Aug. 26, 2011. The entire contents of each of U.S. applicationSer. No. 14/237,617, International Application No. PCT/SE2012/050896,Swedish Application No. 1250007-0, and Swedish Application No. 1150774-6are hereby incorporated herein by reference in their entirety.

TECHNICAL FIELD

The disclosure generally relates to the field of coating of panels,e.g., building panels. More particular, the disclosure relates to amethod for coating of a floor panel and a floor panel produced by themethod.

FIELD OF APPLICATION

The present disclosure is particularly suitable for use in floatingfloors, which are formed of floor panels with a wood fiber core and athin decorative wear resistant surface. The following description ofprior-art technique, problems of known systems and objects and featuresof the disclosure will therefore, as a non-restrictive example, be aimedabove all at this field of application and in particular at flooringswhich are similar to traditional wood fiber based laminate floorings.

It should be emphasized that the disclosure can also be used in otherapplications as for example wall panels, ceilings, and furniturecomponents and similar.

KNOWN TECHNOLOGY

Traditional laminated panels P intended to be used for e.g., flooring,wall panels or furniture components are produced by the following stepsas shown in FIG. 1 a:

-   -   applying a melamine formaldehyde resin impregnated kraft paper        as a balancing layer 4 on one side of a core 3 of wood fiber        based material;    -   applying a by melamine formaldehyde resin impregnated printed        décor paper 2 on the other side of the core 3;    -   applying a melamine formaldehyde resin impregnated transparent        overlay paper 1 with wear resistant particles, for example        aluminum oxide, on the décor paper; and    -   curing the resins by applying heat and pressure in a continuous        or discontinuous press to obtain a laminated product.

Typical press parameters are 40 bar pressure and a temperature of160-200° C. with a pressing time of 12-30 seconds. Pressing of the topsurface is generally made against an embossed press plate that createdthe surface structure of the panel. The décor paper that prior toimpregnation has a weight of 60-80 g/m² comprises generally about 50 wt% of melamine formaldehyde thermosetting resins. The resin content inthe overlay may be even higher.

It is also known that an unimpregnated décor paper may be used to reducethe impregnation cost and to increases the stock lifetime of the printeddecor paper since an impregnated paper has a maximum shelf lifetime of6-12 months. Other disadvantages related to impregnated decorativepapers are that the paper must be stored in a climate controlledwarehouse in order to avoid sticking, that a minimum quantity of about 3tons have to be impregnated in order to obtain low production costs andthat the decorative paper swells and shrinks during impregnation andthis creates problems when the printed patter must be adapted to a panelsize or the embossing pattern of the press plates.

As an alternative to the overlay paper, it is known to apply themelamine formaldehyde resin and the wear resistant particles on top ofthe decor paper in liquid form that subsequently is dried prior topressing or in dry powder form mixed with for example wood fibers. Sucha protective layer is referred to as “liquid overlay” or “powderoverlay”.

Furthermore it is known to apply an unimpregnated décor paper directlyto the board and then add resin in wet liquid form in several steps onthe board and on the décor paper, with intermediate drying zones toremove the water from the resin. The impregnation is made in line withthe pressing operation

It is also known, as shown in FIG. 1b that an impregnated core paper maybe applied as sublayer 12 under a decorative unimpregnated paper andthat resins from the core paper may penetrate into the decorative paperduring pressing. This production method is complicated and not costefficient.

Traditional laminate floorings use a decorative paper that is printedprior to impregnation. Even when unimpregnated papers may be used, suchpapers are printed in separate printing operations and are thereafterapplied on a core prior to pressing. Such printing gives thedisadvantage that the decorative paper has to be positioned precisely onthe core in order to match the embossed surface of the press plate orthe size of the machined floor panel.

FIGS. 1c and 1d show that digital printing technology based on anon-contact process where a digital printing device 9 comprising a printhead, usually a so called Piezo head, fires small drops of inkcomprising a color substance on a substrate 2, may be used to create adécor. The major advantage is the production flexibility, which allowsthat small production volumes can be economically manufactured.

The digital print 8 is generally applied on a paper 2, which is alreadycoated with a base layer comprising a base color or directly on thepanel core, which generally also comprises a base layer. The digitalprint is covered by a transparent protective layer that may be aconventional overlay or a UV cured transparent lacquer.

Digital printing may also be used to print on the overlay paper sheet.The decorative paper provides the base coat and the print on the lowerside of the impregnated overlay provides an additional pattern that isrequired to create a wood or stone design.

The decorative paper 2 or the overlay may be printed digitally priorimpregnation 20 as shown in FIG. 1c or after impregnation 20 as shown inFIG. 1d . The end result is always that a digitally printed décor 8 isapplied on a paper based print carrier 2 that is impregnated andthereafter applied as a separate printed and impregnated sheet on thecore 3.

DEFINITION OF SOME TERMS

In the following text, the visible surface of the installed floor panelis called “front side”, while the opposite side of the floor panel,facing the sub floor, is called “rear side”. By “up” is meant towardsthe front side and by “down” towards the rear side. The sheet-shapedmaterial that comprises the major part of a floor panel is called“core”. By “surface layer” is meant all layers applied to the coreclosest to the front side and covering preferably the entire front sideof the floorboard. By “decorative surface layer” is meant a layer, whichis mainly intended to give the floor its decorative appearance. “Wearlayer” or “protective layer” relates to a layer, which is mainly adaptedto improve the durability of the front side. By “raw paper” is meantunimpregnated paper that does not comprise any thermosetting binders ora paper that only comprises small amounts of thermosetting binders forexample less than about 20 wt % and where a considerable part of theresin content in the pressed paper is injected during pressing from alayer above and/or below the paper.

SUMMARY AND OBJECTS

An overall objective of the present disclosure is to provide an improvedmethod for coating of panels. A specific objective is to avoidimpregnation of the decorative paper and to eliminate the need for aprecise positioning of the decorative paper on the core prior topressing.

The present disclosure combines process flexibility and product featuresas listed a-d below.

The drawback of all known technologies using printed paper is that thereis no method that combines maximum process flexibility and productfeatures in terms of a) the use of unimpregnated or raw papers b) addingflexibility to the process by being able to choose the decor in thepress line by printing the decor digitally with an inkjet printer, c)giving the surface of the pressed board a structure by using an embossedpress plate that forms the board during pressing when the thermosettingresins are cured and d) giving the product impact and wear resistance asgood as or better as traditional direct laminated panels.

By printing the décor after the paper is positioned on the coreincreases the accuracy of décor position and makes it possible to obtainan improved surface design. Avoiding impregnation of the paper givescost advantages and increased production flexibility.

A first aspect of the disclosure is a method for producing a laminatedproduct, for example a building panel, preferably a floor panel, whereinthe method comprising the steps of:

-   -   applying a paper on one side of a wood fiber based core, e.g.,        an HDF panel,    -   creating a décor on the paper by a digital printing process,    -   applying a resin, preferably a melamine formaldehyde resin, on        the paper;    -   heating the décor and the paper with the resin, preferably by        using an IR lamp; and    -   applying heat and pressure in order to cure the resin and        thereby obtain a laminated product.

Preferably, the step of creating the décor by the digital printingprocess is performed after the paper is applied to the core.

The method may further comprise the step of applying a powder based sublayer on the core and under the paper. Said powder based sub layercomprising wood fibers and a thermosetting powder resin, preferably amelamine formaldehyde resin.

The powder sub based layer preferably comprises about 50 wt % woodfibers and about 50 wt % melamine resin (e.g., Kuaramin 773).

Alternatively the powder sub layer may preferably comprise about 60-80wt % wood fibers and 20-40 wt % melamine/urea resins.

The method may further comprise the step of applying moisture on thepowder based sub layer and thereafter applying heat in order to dry thepowder based sub layer.

The method may further comprise the steps of:

-   -   applying a liquid resin, preferably a melamine formaldehyde        resin, on the core; and    -   drying the liquid resin, preferably by using an IR lamp, before        the paper is applied on the core.

The resin applied on the paper may be in powder or liquid form. Theresin in powder form may be included in a mix comprising wood fibers andsaid resin for forming a powder based overlay.

The method may further comprise the step of creating a décor on thepowder resin applied on the paper by a digital printing process. Thisstep may replace the printing on the paper.

The surface weight of the powder on the paper is preferably about 200g/m.

The method may further comprise the step of applying moisture on theresin in powder form.

The method may further comprise the step of applying wear resistantparticles, preferably aluminum oxide particles, on the paper beforeheating the décor.

The method may further comprise the step of applying additive particles,such as submicron particles based on silica or aluminum oxides, toimprove the scuff resistance, on the paper before heating the décor.

The method may further comprise the step of applying cellulose fibers,preferably alpha cellulose fibers, on the paper, before heating thedécor.

The method may further comprise the step of applying a layer on theother side of the core, before applying heat and pressure, to obtain abalancing layer.

The balancing layer may be a powder layer comprising wood fibers and aresin or a paper.

The surface weight of paper for the décor is preferably about 60, 70, 80or 85 g/m². Even thinner papers may be used with a surface weight ofabout 40 to 60 g/m², preferably 40 to 50 g/m².

The solid content of the resin is preferably in the range of about 50±10wt %., more preferably 50±2 wt %.

The digital print may be a non-contact process comprising a Piezo printhead that applies water-based drops. The color pigments may be appliedin a separate step in dry form. The color pigments may be bonded by thewater drops.

The press parameters may be in the range of about 20-60 bar, preferablyabout 40 bar and the temperature in the range of about 160-200° C.,preferably about 180° C., with a pressing time of about 12-30 seconds.

As disclosed in WO2009/124704 it is also possible to add a layer of apowder mixture comprising wood powder, dry resin and potentially otheradditives under the décor paper to increase impact resistant, allowdeeper embossing and to impregnate an unimpregnated décor paper frombelow during the curing process in the press.

A second aspect of the disclosure is a floor panel produced according tothe first or the third aspect.

A third aspect of the disclosure is a method for producing a laminatedproduct, for example a building panel, preferably a floor panel, whereinthe method comprising the steps of:

-   -   applying a powder based sub layer comprising wood fibers and a        thermosetting resin on a wood fiber based core, e.g., an HDF        panel,    -   applying a raw paper on the powder based sub layer,    -   applying a protective powder based or paper based overlay        comprising a melamine formaldehyde resin and aluminum oxide on        the raw paper;    -   applying heat and pressure in order to impregnate the raw paper,        to cure the resin and thereby obtain a laminated product.

The method may further comprise the step applying a powder basedbalancing layer comprising wood fibers and a thermosetting resin on arear side of the core.

In one embodiment, the overlay may be a powder based overlay, and apaper overlay may be applied on the powder based overlay.

A fourth aspect of the disclosure is a floor panel comprising a core, abalancing layer on a rear side of said core, and a surface layer on afront side of said core. The surface layer comprises a decorative paper,a protective transparent paper, a first powder based sub layer arrangedunder the decorative paper, and a second powder based sub layer arrangedbetween the decorative paper and the protective transparent paper. Thefirst and the second sublayers comprise fibers having an average length,which is smaller than the average length of the fibers in the decorativeand overlay papers.

The balancing layer may be a powder based balancing layer comprisingwood fibers. The wood fibers may in all embodiments be in powder form.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1a-1d illustrate known laminated floor panels.

FIGS. 2a-2d illustrate a first embodiment of the invention.

FIGS. 3a-d illustrate a second embodiment of the invention.

FIGS. 4a-4d illustrate a third embodiment of the invention.

FIGS. 5a-5c illustrate forming of the surface layer.

DESCRIPTION OF EMBODIMENTS OF THE INVENTION

The disclosure will in the following be described in connection toexemplary embodiments.

FIGS. 2a -2d show a first embodiment of the invention.

FIG. 2a shows a panel P comprising a core 3, preferably a HDF core and abalancing layer 4 on the rear side of the core 3. The balancing layer 4may be a conventional kraft paper impregnated with a thermosettingresin, preferably a melamine formaldehyde resin, or a powder backingcomprising wood fibers and a thermosetting resin, preferably a melamineformaldehyde resin. The application of a powder backing is made by ascattering unit 10 in the same way as shown in FIG. 4a . The spraying 11and the drying device 7 will stabilize the powder and create a balancinglayer 4 that may be connected to the core 3 such that the panel P may beturned with the rear side pointing downwards prior to the application ofthe surface layers 1, 2, 12. A resin 5, preferably a liquidthermosetting resin that preferably is a melamine formaldehyde resin, isapplied on the upper side of the core 3, preferably with a roller 6 orby spraying. The resin is heated and dried by using a drying device 7such as for example an IR lamp, hot air, microwaves and similar.

FIG. 2b shows a paper layer 2 that is applied on the dried resin. Thepaper is preferably a raw paper. The paper may comprise a basic color ormay be partly printed. It is not necessary to align the paper preciselysince there is no final printed pattern on the paper 2.

FIG. 2c shows a digital print 8 that is printed on the paper 2 by adigital printing device 9. Digital printing is a non-contact processwhere a digital print head, preferably a Piezo head, fires drops of aliquid substance on a substrate and creates a pattern. The liquidsubstance may comprise color pigments and may be water based.Alternatively the pigments may be applied separately in dry powder formand the digital print head may essentially only apply a liquid substancethat may be transparent and that may comprise a substance that acts as abinder and connects the pigments to the substrate. Non-bonded pigmentsmay be removed by for example an air stream or gravity. Such a two-stepdigital binder and powder (BAP) printing is very cost efficientespecially when large amounts of pigments are used to create a pattern.BAP allows that substantial amounts of pigmented powder may be appliedfor example more than 20 g/m² preferably about 20-50 g/m².

FIG. 2d shows that the paper 2 is coated with a liquid thermosettingresin, preferably a melamine formaldehyde resin, in order to create aprotective layer 1 similar to a conventional overlay. The coating ispreferably made in the same way as shown and described in FIG. 2a . Theliquid resin comprises preferably aluminum oxide particles and/orcellulose fibers preferably alpha cellulose fibers.

A coating of the paper with a base color may also be made prior to thedigital printing.

The first embodiment of the method comprises the step of:

-   -   coating of a wood fiber based core 3, preferably an HDF panel,        with a liquid melamine formaldehyde resin;    -   drying the liquid resin;    -   attaching a paper 2 to the core 3;    -   providing a décor 8 on the paper 2 by a digital printing        process;    -   coating the paper 2 with the decor with a liquid melamine resin,        preferably comprising aluminum oxide particles and/or cellulose        fibers preferably alpha cellulose fibers;    -   drying the coating; and    -   applying heat and pressure to cure the resins and thereby obtain        a laminated product.

An advantage is that it is possible to use an unprinted paper, whichreduces the warehouse costs and improves the process flexibility. Byprinting the paper after the paper is attached to the core the accuracyof the décor position is improved.

The coating of the paper may be replaced or combined with a conventionaloverlay that is applied over the digitally printed paper.

FIGS. 3a-3d show a second embodiment of the invention. The forming ofthe balancing layer 4, the coating of the core 3 and the digitalprinting of the paper as shown in FIGS. 3a-3c are the same as in thefirst embodiment. However, the protective layer 1 has been replaced witha powder overlay that is scattered by a scattering unit 10 in dry formover the paper 2 with the digital print 8 as shown in FIG. 3d . Saidpowder overlay preferably comprising fibers, preferably processed woodfibers, a resin, preferably a melamine formaldehyde resin, and wearresistant particles, preferably aluminum oxide. A liquid substancepreferably comprising water may be sprayed on the powder overlay by aspraying device 11 and dried by a drying device 7 in order to stabilizethe powder prior to the pressing operation.

The second embodiment of the first aspect of the method comprises thestep of:

-   -   coating of a wood fiber based core 3, preferably an HDF panel,        with a liquid melamine formaldehyde resin;    -   drying the liquid resin;    -   attaching a paper 2 to the core 3;    -   providing a décor 8 on the paper 2 by a digital printing        process;    -   applying a powder overlay 1 on the printed décor paper 2, said        overlay 1 preferably comprising fibers, a resin, preferably a        melamine formaldehyde resin, and wear resistant particles,        preferably aluminum oxide,    -   applying moisture on the powder overlay 1;    -   drying the powder overlay 1; and    -   applying heat and pressure to cure the resins and thereby obtain        a laminated product.

A further advantage with the second embodiment is that the impactresistance is improved due to the substantial amounts of fibers in theresin matrix, obtained from the powder overlay.

FIGS. 4a-4d show a third embodiment of the invention. FIG. 4a shows thata powder sublayer 12 comprising a wood fibers and a thermosetting resin,preferably a melamine formaldehyde resin or a melamine/urea resin isapplied on the upper side of the core 3. The balancing layer 4 may be apaper or a powder backing as described above. The sublayer 12 may beapplied in the same way as the powder overlay with a scattering unit 10.Preferably a spraying device 11 that applies moisture on the powder anda drying device 7 may also be used to stabilize the powder in order tofacilitate the application of the paper 2 over the powder sub layer 12.FIGS. 4c and 4d show that the paper 2 is provided with a digital print 8by a digital printing device 9 and preferably with a powder overlay 1 ora conventional paper overlay 1 as described above. The powder overlay 1may be applied by a scattering unit 10, sprayed with water by a sprayingdevice 11 and dried by a drying device 7.

The third embodiment of the method comprises the step of:

-   -   applying a powder based sublayer 12 on a core 3, preferably an        HDF panel, and preferably applying moisture on the sublayer and        thereafter drying the sublayer;    -   attaching a paper 2 on the sublayer 12;    -   providing a décor 8 on the paper 2 by a digital printing        process;    -   applying a powder overlay 1 on the printed décor paper 2, said        overlay preferably comprising fibers, a resin, preferably a        melamine formaldehyde resin, and wear resistant particles,        preferably aluminum oxide,    -   applying moisture on the powder overlay 1;    -   drying the powder overlay 1; and    -   applying heat and pressure to cure the resins and thereby obtain        a laminated product.

A further advantage with the third embodiment is that the demand fordrying is decreased since no wet resins are applied. The sub layer 12gives an increased impact resistance and possibility to form a surfacewith deep embossing. The sub layer 12 is a cost efficient way to providea sufficient amount of binders that may penetrate into the paper 2during pressing

The surface weight of the powder overlay is preferably about 200 g/m²but may be as low as 50 g/m² or exceed 400 g/m². The weight of the sublayer is preferably 100-500 g/m².

The invention makes it possible to reduce the weight of the décor papersince no impregnation is needed and there is no need for a high “wetstrength”. The weight of the raw paper may be lower than 60 g/m²preferably about 40 to 50 g/m². The press parameters in the threeembodiments above are preferably about 40 bar and the temperature in therange of about 160-200° C., preferably about 180° C., with a pressingtime of about 10-30 seconds depending on the layer thickness.

FIG. 5a shows the surface layer prior to pressing according to the thirdaspect of the invention. The sub layer 12 comprises in this embodimentwood fibers 14, dry thermosetting resin particles 15 and preferably alsocolor pigments 13 that give the sub layer a basic color and preventsthat the core surface is visible through the thin paper. This reducesthe requirement on the digital print 8 and the print may be made withlower ink content, preferably with an ink content of less than 10 g/m².The powder overlay 1, which is applied over the paper 2 with the digitalprint 8, comprises aluminum oxide particles 16, wood fibers 14 and resinparticles 15. FIG. 5b shows the surface layer after pressing. The powderhas been compressed and the pressed surface layer has in this embodimentpreferably a thickness T2 that is less than about 80% and even morepreferably less than about 50% of the surface thickness T1 prior to thepressing. The compression of the powder under heat and pressure, whenthe powder resin 15 becomes fluid, impregnates the paper 2 from aboveand from below and connects the surface layers to the core 3.

The basic principles of the invention to use a powder sub layer 12 toimpregnate a raw paper 2 during pressing may also be used even withoutthe digital printing to produce a surface with a conventional rawdecorative printed paper and preferably also with conventional overlayand/or a conventional balancing paper.

A preferred embodiment is a panel P comprising a powder based balancinglayer 4, a powder based sub layer 12 on the upper part of the core 3, araw decorative paper 2 applied on the powder based sub layer 12 and aprotective overlay 1 on the raw decorative paper.

The powder based balancing layer 4 gives an improved balancing of thepanel P since the fiber properties and orientation in the balancinglayer 4 and the sub layer 12 may be similar and may result in the sameshrinking after pressing and in different climate conditions. Theprotective overlay 1 may be a powder or paper based protective layer asdescribed in the embodiments above.

FIG. 5c shows a surface layer comprising a powder overlay 1 a and apaper overlay 1 b applied on the powder overlay. Preferably the paperoverlay 1 b is a raw paper which during pressing is impregnated withresins from the powder overlay 1 a under the paper overlay 1 b. Theadvantage is that the paper overlay 1 b protects the press plates fromthe wear caused by the aluminum oxide particles. Very thin overlaypapers may be used with a weight of 20-30 g/m².

The surface layer according to this embodiment comprises a first powderbased sub layer 12 under a decorative paper 2 and a second powder basedsub layer 1 a under a transparent paper located above the decorativepaper 2.

A powder based layer is characterized in the mechanically processedfibers have an average length of about less than 1 mm. Fibers used in anHDF core or in paper are longer and have an average length of severalmm. The surface of the panel P is characterized in that the fibers infirst 12 and second 1 a sub layers are smaller than the fibers in thedecorative paper the paper overlay.

Several alternatives are possible. The powder overlay 1 a may onlycomprise melamine formaldehyde resins and aluminum oxide particles. Itmay also comprise bleached transparent wood fibers. The paper overlaymay be a conventional impregnated overlay with or without aluminum oxideparticles.

The second sublayer 1 a will improve the wear and impact resistance evenin the case when a conventional overlay is used.

A raw and essentially transparent paper overlay may also be used as aprint carrier. A digital print 8 is applied on the print carrier. Theprint may be applied prior to or after the application of the rawoverlay on the core. The raw overlay is preferably applied on a powderbased sub layer 12 comprising fibers 14, a thermosetting resin 15, andcolor pigments 13. A powder overlay or a second conventional overlay maybe applied on the raw overlay as a protective layer 1. The raw overlayis during pressing impregnated from the resins in the sub layer 12 andin the protective layer 1.

EXAMPLE

In example 1 below the powder mix formulation for the balancing layer 4and the first sub layer 12 used comprising 50 weight-% recycled MDFfibers (Välinge Innovation Sweden), 50 weight-% Melamine Formaldehyderesin (Preferably 4865, Dynea). The powder formulation for the secondsub layer 1 a used comprises processed bleached wood fibers of about 25wt %, 65 wt % of melamine formaldehyde resin and 10 wt % of aluminumoxide particles

Example 1 Powder Based Panel Obtained Through Heat and Pressure

A balancing layer 4 and a first sub layer 12 was formed by scattering300 g/m² of powder on the rear side and the front side of a 9.7 mm HDFcore.

A raw decorative paper 2 with a weight of 60 g/m² was applied on thefirst sub layer 12 and a second sub layer 1 a was applied on thedecorative paper by scattering 200 g/m² of powder.

A 25 g/m² raw overlay was applied on the second sub layer 1 a.

The core with the surface and balancing layers was pressed in a presswith a pressure of 40 kg/cm², during 20 seconds. The upper press tableapplied a heat of 170° C. on the surface layer and the lower press tableapplied a heat of 175° C. on balancing layer. The surface was pressedagainst a press plate with an embossing depth of 0.3 mm.

A panel with an embossed decorative structure and a small pre tensionbackwards and a slightly convex surface was obtained. All raw paperswere impregnated and cured during the pressing operation.

EMBODIMENTS

1. Method for producing a laminated product, for example a buildingpanel, preferably a floor panel (P), wherein the method comprising thesteps of:

-   -   applying a paper (2) on one side of a wood fiber based core (3),        e.g., an HDF panel,    -   creating a décor (8) on the paper (2) by a digital printing        process,    -   applying a resin (5), preferably a melamine formaldehyde resin,        on the paper (2);    -   heating the décor (8) and the paper (2) with the resin (5),        preferably by using an IR lamp (7); and    -   applying heat and pressure in order to cure the resin and        thereby obtain a laminated product.

2. The method as in embodiment 1, wherein the method further comprisesthe step of applying a powder based sub layer (12) on the core (3), saidpowder based sub layer (12) comprising wood fibers and a powder resin,preferably a melamine formaldehyde resin, before the paper (2) isapplied on the core (3).

3. The method as in embodiment 2, wherein the method further comprisesthe step of applying moisture on the powder based sub layer (12) andthereafter applying heat in order to dry the powder based sub layer(12).

4. The method as in embodiment 1, wherein the method further comprisesthe steps of:

-   -   applying a liquid resin (5), preferably a melamine formaldehyde        resin, on the core (3); and    -   drying the liquid resin (5), preferably by using an IR lamp (7),        before the paper (2) is applied on the core (3).

5. The method as in any one of the preceding embodiments, wherein theresin (5) applied on the paper (2) is in powder form.

6. The method as in embodiment 5, wherein the method further comprisesthe step of applying moisture on the resin (5) in powder form.

7. The method as in any one of the preceding embodiments, wherein themethod further comprises the step of applying wear resistant particles(16), preferably aluminum oxide particles, on the paper (2) beforeheating the décor (8).

8. The method as in any one of the preceding embodiments, wherein themethod further comprises the step of applying cellulose fibers,preferably alpha cellulose fibers, on the paper, before heating thedécor (8).

9. The method as in any one of the preceding embodiments, wherein themethod further comprises the step of applying a balancing layer (4) onthe other side of the core (3), before applying heat and pressure, toobtain a balancing layer.

10. The method as in embodiment 9, wherein the balancing layer (4) is apowder layer comprising wood fibers and a resin or a paper.

11. The method as in embodiments 2 or 3, wherein the paper (2) is a thinraw paper with a weight of about 40-60 g/m².

12. The method as in embodiment 2 or 3, wherein the paper (2) is a thinraw paper with a weight of about 40-50 g/m².

13. The method as in any one of the preceding embodiments, wherein adigital non-contact process is used comprising a Piezo print head thatapplies water based drops.

14. The method as in embodiment 13, wherein color pigments (13) areapplied in a separate step in dry form and bonded by the water baseddrops.

15. The method as in any one of the preceding embodiments, wherein thestep of creating the décor (8) by the digital printing process isperformed after the paper (2) is applied to the core (3).

16. Method for producing a laminated product, for example a buildingpanel, preferably a floor panel (P), wherein the method comprising thesteps of:

-   -   applying a powder based sub layer (12) comprising wood fibers        and a thermosetting resin on a wood fiber based core (3), e.g.,        an HDF panel,    -   applying a raw paper (2) on the powder based sub layer (12),    -   applying a protective powder based or paper based overlay (1)        comprising a melamine formaldehyde resin and aluminum oxide on        said raw paper (2);    -   applying heat and pressure in order to impregnate the raw paper        (2), to cure the resin and thereby obtain a laminated product.

17. The method as in embodiment 16, wherein a powder based balancinglayer (4) comprising wood fibers and a thermosetting resin is applied ona rear side of the core (3).

18. The method as in embodiment 16 or 17, wherein said overlay (1) is apowder based overlay (1 a), and wherein a paper overlay (1 b) is appliedon the powder based overlay (1 a).

19. A floor panel (P) comprising:

-   -   a core (3), preferably a wood fiber based core,    -   a balancing layer (4) on a rear side of said core (3), and    -   a surface layer on a front side of said core (3), said surface        layer comprising a decorative paper (2), a protective        transparent paper (1 b), a first powder based sub layer (12)        arranged under the decorative paper (2), and a second powder        based sub layer (1 a) arranged between the decorative paper (2)        and the protective transparent paper (1 b),    -   wherein the first and the second sub layers (12, 1 a) comprise        fibers having an average length which is smaller than the        average length of the fibers in the decorative and overlay        papers (2, 1 b).

20. A floor panel (P) as in embodiment 19, wherein the balancing layer(4) is a powder based balancing layer comprising wood fibers.

The invention claimed is:
 1. A method for producing a laminated product,the method comprising: applying a powder-based sublayer comprising woodfibers and a thermosetting resin on a wood fiber based core; applying apaper on the powder-based sublayer, wherein the paper is anunimpregnated paper when the paper is applied on the sublayer; applyinga protective overlay comprising a thermosetting resin and wear-resistantparticles on the paper; and applying heat and pressure in order toimpregnate the paper, to cure the resins, and thereby obtain a laminatedproduct.
 2. The method according to claim 1, wherein a secondpowder-based balancing layer is applied on a rear side of the core. 3.The method according to claim 2, wherein the second powder-basedbalancing layer comprises wood fibers and a thermosetting resin.
 4. Themethod according to claim 1, wherein a paper-based balancing layer isapplied on a rear side of the core.
 5. The method according to claim 1,wherein the protective overlay is a powder-based overlay.
 6. The methodaccording to claim 5, wherein a paper overlay is applied on thepowder-based overlay.
 7. A method for producing a laminated product, themethod comprising: applying a powder-based sublayer comprising woodfibers and a thermosetting resin on a wood fiber based core; applying apaper on the powder-based sublayer, wherein the paper is anunimpregnated paper when the paper is applied on the sublayer; applyinga protective overlay comprising a thermosetting resin and wear-resistantparticles on the paper; and applying heat and pressure in order toimpregnate the paper, to cure the resins, and thereby obtain a laminatedproduct, wherein the protective overlay is a powder-based overlay, andwherein the powder-based overlay is applied by scattering.
 8. The methodaccording to claim 5, further comprising applying moisture on thepowder-based overlay and drying the powder-based overlay.
 9. The methodaccording to claim 1, further comprising applying moisture on thepowder-based sublayer and drying the powder-based sublayer.
 10. Themethod according to claim 1, wherein the protective overlay is apaper-based overlay.
 11. The method according to claim 1, furthercomprising providing a decor on the paper by a digital printing process.12. The method according to claim 1, wherein the sublayer furthercomprises color pigments.
 13. The method according to claim 1, whereinprotective overlay further comprises wood fibers.
 14. A method forproducing a laminated product, the method comprising: applying apowder-based sublayer comprising wood fibers and a thermosetting resinon a wood fiber based core; applying a paper on the powder-basedsublayer, wherein the paper is an unimpregnated paper when the paper isapplied on the sublayer; applying a protective overlay comprising athermosetting resin and wear-resistant particles on the paper; andapplying heat and pressure in order to impregnate the paper, to cure theresins, and thereby obtain a laminated product, wherein the powder-basedsublayer is applied by scattering.
 15. The method according to claim 1,wherein the powder-based sublayer is a first sublayer and wherein themethod further comprises: applying a second powder-based sublayer on thepaper, and applying a transparent paper on the second powder-basedsublayer.
 16. The method according to claim 1, wherein the thermosettingresin and wear-resistant particles of the protective overlay comprises amelamine formaldehyde resin and aluminum oxide.
 17. The method accordingto claim 1, wherein the thermosetting resin of the sublayer comprisesmelamine formaldehyde resin or a melamine/urea resin.
 18. The methodaccording to claim 1, wherein the wood fiber based core is an HDF panel.19. The method according to claim 1, wherein the laminated product is abuilding panel or a floor panel.